The present application claims the priority of the commonly owned copending German patent application Serial No. 100 31 848.7 filed Jul. 4, 2000. The disclosure of the above-referenced German patent application, as well as that of each U.S. and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
The present invention relates to improvements in methods of and in apparatus for manipulating (processing) so-called tows or analogous accumulations of acetate fibers or other suitable filamentary filter material for tobacco smoke. More particularly, the invention relates to improvements in methods of and in apparatus for treating tows of filamentary filter material for tobacco smoke on their way from one or more sources (such as bales of compacted tow) to the wrapping mechanism of a filter rod making machine wherein successive increments of the duly processed tow are draped into successive increments of a running web or strip of cigarette paper or other suitable wrapping material for a continuous rod-like filler of filter material.
As a rule, and as disclosed, for example, in U.S. Pat. No. 3,974,007 (granted Aug, 10, 1976 to Greve for xe2x80x9cMETHOD AND APPARATUS FOR THE PRODUCTION OF FILTER ROD SECTIONS OR THE LIKExe2x80x9d) and U.S. Pat. No. 4,412,505 (granted Nov. 1, 1983 to Hxc3xa4usler et al. for xe2x80x9cAPPARATUS FOR APPLYING ATOMIZED LIQUID TO A RUNNING LAYER OF FILAMENTARY MATERIAL OR THE LIKExe2x80x9d), a tow of acetate fibers is drawn from a bale and advances along an elongated path first through an expanding or stretching unit wherein the originally crimped and interlaced filaments undergo a straightening or lengthening or stretching action between a pair of relatively slow rotary trailing or rear rolls and a pair of relatively rapidly driven front rolls. The thus stretched filaments are advanced through an applicator which sprays a suitable finely atomized plasticizer (such as triacetin) onto and thus causes localized melting of the material of which the filaments are made. The thus treated tow is converted into a rod-like filler wherein softened portions of neighboring filaments adhere to each other to establish a maze of discrete paths for the flow of tobacco smoke between the lighted end of a filter cigarette, cigar or cigarillo and the mouth of the smoker. Conversion of the flattened tow of stretched filaments into a rod-like filler is effected, at least in part, by a so-called gathering horn which precedes the wrapping station. Reference may also be had to published German patent application Serial No. 198 11 014.
U.S. Pat. No. 5,590,449 (granted Jan. 7, 1997 to Chehab et al. for xe2x80x9cAPPARATUS FOR STRETCHING, PLASTICIZING AND GATHERING A TOW OF FILTER MATERIAL FOR TOBACCO SMOKExe2x80x9d) further discloses a so-called gathering unit which is installed between the plasticizer applicator and the aforementioned gathering horn upstream of the wrapping station.
A drawback of presently known filter rod making apparatus is that they are likely to contaminate the surrounding area with fragments of filamentary filter material for tobacco smoke. Moreover, the filaments of the running tow are likely to carry out undesirable stray movements which can affect the distribution of such filaments in the rod-like filler.
An object of this invention is to provide a novel and improved method of treating the filaments of a running tow of filamentary filter material for tobacco smoke with a view to expel from the tow and to preferably gather any such fragments of filter material which are not desirable in the tubular envelope of the mouthpiece of a filter cigarette, cigar or cigarillo.
Another object of the invention is to provide a novel and improved method of preventing turbulent air from influencing a filter tow successive increments of which advance toward the wrapping station in a filter rod making machine.
A further object of the invention is to provide a novel and improved filter rod making machine,
An additional object of the invention is to provide a novel and improved turbulence preventing or reducing arrangement which counteracts undesirable stray movements (such as fluttering) of filaments in a running tow of filamentary filter material for tobacco smoke.
Still another object of the invention is to provide a novel and improved combination of tow advancing and filament constraining means for use in a filter rod making machine.
A further object of the present invention is to provide a novel and improved filter cigarette, cigar, cigarilo or an analogous smokers"" product wherein tobacco smoke must pass through a mouthpiece containing filter material for tobacco smoke.
Another object of the invention is to provide a novel and improved method of relieving a flow or tow of filamentary filter matrial for tobacco smoke of short filaments which have been partly separated from and/or which are still embedded in the satisfactory part of the tow.
Still another object of the invention is to prevent or at least reduce the likelihood of contamination of air in the region of a filter rod making machine by particles of filter material for tobacco smoke,
A further object of this invention is to provide a smokers"" product which can be mass produced in a novel and improved filter rod making machine in such a way that the surrounding atmosphere is not contaminated with fragments of fibrous filter material for tobacco smoke.
One feature of the present invention resides in the provision of a method of manipulating a running tow of filamentary filter material for tobacco smoke. This method comprises the steps of advancing the tow lengthwise in a predetermined direction (e.g., downwardly) along an elongated path including conveying the tow through the nip of at least one set of advancing members (e.g., two driven rolls), and withdrawing air from a region of the path at the nip.
The withdrawing step can include evacuating air from the path directly at the nip of the advancing members. The path for the tow includes a first portion immediately upstream and a second portion immediately downstream of the nip; the withdrawing step can include evacuating air from the just mentioned portions of the path.
Another feature of the present invention resides in the provision of a method of manipulating a running tow of filamentary filter material for tobacco smoke. The method comprises the step of advancing the tow lengthwise in a predetermined direction along an elongated path, and this advancing step includes conveying the tow through the nip of a first set of advancing members (e.g., a pair of driven rolls) adjacent a first portion of the path and thereafter through the nip of a second set of advancing members (e.g., a pair of driven rolls) adjacent a second portion of the path downstream of the first portion as seen in the predetermined direction. The method further comprises the step of withdrawing air from the region of the nip of at least one of the first and second sets of advancing members.
The at least one set is or can be the second set of advancing members.
The withdrawing step can further include withdrawing air solely from the region of the nip of the second set of advancing members.
A further feature of the present invention resides in the provision of an apparatus for manipulating a running tow of filamentary filter material for tobacco smoke. The improved apparatus comprises means for advancing the tow lengthwise in a predetermined direction along a predetermined path including at least one set of advancing members defining a nip for the running tow at a predetermined section of the path, and means for withdrawing air from the region of the nip.
The advancing members can constitute pairs of driven rolls and the withdrawing means can include means for withdrawing air from at least one portion of the path immediately adjacent the nip.
For example, the withdrawing means can include a substantially funnel shaped air withdrawing member (e.g., a nozzle) having an air intake at the nip and a configuration which is at least substantially complementary to that of the advancing means at the nip.
The aforementioned section of the path for the tow includes a first portion immediately upstream and a second portion immediately downstream of the nip. The withdrawing means can include means for evacuating air from the first and second portions of the section of the path.
The advancing means can further include a second set of advancing members (such as two driven rolls) which are spaced apart from the at least one set of advancing members. The at least one set of advancing members is or can be disposed downstream of the second set of advancing members (as seen in the predetermined direction of forward movement of the tow). Such apparatus can further include a channel which at least partially surrounds the path between the two sets of advancing members and has a discharge end at the at least one set of advancing members.
The channel can at least partially confine a tow gathering unit and/or a tow stretching unit of the improved apparatus.
One set of the advancing members can be installed at a level above the other set of advancing members.
It has been found that the improved apparatus can be utilized with advantage in connection with the processing of tows which consist of or contain acetate fibers.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling, installing and operating the same, together with numerous additional important and advantageous features and attributes thereof, wil be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.